Over 5,000 asteroids exist in near-Earth space. Many of these objects are more easily accessible than the surface of the moon. These bodies record the ancient history of our solar system and represent the largest potential natural disaster facing mankind. In addition, they represent significant natural resources for space exploration in the form of water, hydrocarbons, metals and building materials. Over the coming decades, these objects may be the target of intense exploration to discern their ancient history and pave the way for large-scale human settlement of space.